Accordingly, this invention is directed to a handle shaft joint which enables the power driven tool of an implement to be conveniently separate from its power driving end, to be angularly positioned relative thereto in some instances and/or to be replaced by a like or different implement or tool head.
Shipping elongated implements are not only inconvenient to handle, but are more costly to package than smaller structures. Further, a common power driving end of an implement that can be used with a number of implement heads or tools makes the device saleable to a larger number of prospective buyers and for a larger variety of uses without substantially increasing the costs involved.
With regard to weed and grass trimmers using a flailing line for cutting purposes now widely used for many different kinds of trimming purposes, such as around obstacles and edging, the plane occupied by the rotating flail is differently oriented. Sometimes it is adjusted for horizontal trimming and at other times for vertical trimming or at an angle in between these two positions.
One conventional flailing line trimmer comprising an engine or motor mounted on the outboard end of a handle shaft employs a flexible cable that passes through the handle shaft from the motor to the drive head of the flailing line. A grip on the handle shaft permits the operator to maneuver the plane of the rotating cutting line by tilting the drive head at whatever angle is necessary. In other conventional devices, both the motor and the drive head are located at the distal end of the handle shaft.
A difficulty in the use of such trimmers is that the weight of the engine makes maneuvering and tilting at various angles tiring, particularly when the engine and the drive head are at opposite ends of the device. The engine is usually mounted and balanced for use in one position relative to the handle, and a positive torque must be applied to tilt the assembly. Also, when an internal combustion engine is used, it may not operate properly if tilted at excessively steep angles. The tilting can affect the flow of fuel which will disturb engine operation or even cause it to stop. It is advantageous for the internal combustion engine to remain in one suitable orientation when the drive head is tilted at various angles relative to the engine to tilt the cutting line. This also reduces operator fatigue. When the motor is carried on the head (then it is usually an electric motor), it is still useful to be able to change the head orientation relative to the handle so the user can have the most effort-free grip on the assembly.